Certificate of Completion

An official document issued by building control confirming that renovation or construction work has been inspected and complies with building regulations.

A certificate of completion (called a “completion certificate” in the UK or a “certificate of occupancy” in parts of the US) is the official document confirming that your renovation work has been inspected and meets all applicable building regulations or building code requirements. It’s issued by building control (UK) or the local building department (US) after their final inspection.

Why it matters

A completion certificate is important because:

  • Legal proof — it confirms your work was carried out lawfully and to the required standard
  • Property sale — when you sell your home, your buyer’s solicitor or attorney will ask for completion certificates for any building work. Missing certificates can delay or jeopardise a sale
  • Insurance — your home insurance may not cover work that wasn’t properly certified
  • Mortgage — lenders may require evidence that work was done to code
  • Peace of mind — an independent professional has confirmed the work is safe and structurally sound

When you need one

You need a completion certificate for any work that required a building regulations application or building permit, including:

  • Structural alterations
  • Extensions and conversions
  • Electrical rewiring or new circuits
  • New heating systems
  • Window and door replacements (in some cases)
  • Plumbing and drainage work

How to get one

  1. Your general contractor notifies building control that the work is complete
  2. A building control officer visits for a final inspection
  3. If the work passes, the completion certificate is issued
  4. If issues are found, they must be corrected and re-inspected

What if you don’t have one

If work was done without a completion certificate — perhaps by a previous owner — you have options:

  • Apply for a regularisation certificate — building control inspects the existing work and certifies it retrospectively (a fee applies, and they may require some work to be opened up for inspection)
  • Indemnity insurance — a policy that covers the risk of enforcement action (commonly used in property transactions, though it’s a workaround rather than a proper solution)

Tips for homeowners

  • Don’t make final payment until the completion certificate has been obtained or is in progress
  • Keep the certificate safe — store it with your property deeds
  • Check for certificates when buying a property — ask the seller’s solicitor for certificates for any visible building work
  • Your contractor should manage this — obtaining the completion certificate is part of finishing the job properly